1. Field of the Invention
The present invention relates to a batch-processing type CVD device of the low-pressure vertical model, and particularly relates to a gas injector (hereinafter referred to as xe2x80x9can injectorxe2x80x9d) and a gas injector holder (hereinafter referred to as xe2x80x9can injector holderxe2x80x9d) within the device.
2. Description of the Related Art
As semiconductor devices have become more highly integrated, reducing a cell area is necessary. In the thin-film forming process, the quality of a film is an important factor for the high integration as well as the homogeneity of film thickness. Particularly in the case of multicomponent thin films (for example, doped-poly Si, SiGe, BST), the homogeneity of the concentration of each constitutive chemical element and doping element has a great influence on the film quality.
Conventionally, an injector has been used to improve the concentration homogeneity of each chemical element in high-productivity batch-processing type CVD devices of the low-pressure vertical model. The injector is to spray a reaction gas to multiple semiconductor substrates at the same time and is fixed within a reaction chamber using a metal injector holder. In this method, however, there is a risk of metal contamination from the injector holder, and it is difficult to employ this method for high-vacuum devices for which high purity is demanded or for processes for next-generation devices.
Additionally conventionally, an injector holder made of SUS (stainless steel) is used to fix an injector made of quartz within the reaction chamber. The injector is fixed by inserting it in the injector holder installed on a gas flange made of SUS (stainless steel). In this method, however, a problem of metal contamination from the injector holder has not been completely solved. For this reason, it is difficult to employ this method for high-vacuum devices for which high purity is demanded or for processes for next-generation devices.
Furthermore, conventionally, to solve the metal contamination problem, an L-shaped integrated injector made of quartz, in which an injector and an injector holder are formed as one, is used. For CVD devices of the typical low-pressure vertical model, the height of a reaction zone is approximately 500 mm. However, the height from a gas inlet to the highest portion of the reaction zone is approximately 1000-1500 mm. In this case, if the angle of the L-shaped portion of the injector deviates by one degree, a gap at the highest portion will become 17-26 mm. Accordingly, when shaping an L-shaped quartz injector by bending, strict accuracy is required, and thus it is not practical to use the L-shaped integrated injector made of quartz for a device which has a small margin between a substrate boat and an inner tube.
Furthermore, for an L-shaped integrated injector made of quartz, because removing a holder portion is necessary when replacing the injector, it takes much care and there is a risk of damaging the injector.
Consequently, an object of the present invention is to provide an injector which can be used for a device with a small margin between a substrate boat and an inner tube and which is not influenced by the accuracy of processing.
Additionally, another object of the present invention is to provide a semiconductor-manufacturing device, which has an injector in which a problem of metal contamination does not occur.
Furthermore, still another object of the present invention is to provide a semiconductor-manufacturing device, which has an injector wherein an injector can be easily replaced without a risk of damaging the injector.
To achieve the above-mentioned objects, a semiconductor-manufacturing device according to the present invention comprises the following means:
That is, in an embodiment of the present invention, a batch-processing type semiconductor-manufacturing device comprises: (a) a cylindrical reaction chamber with its upper end closed and its bottom end open, (b) a substrate-supporting boat for loading multiple substrates which are inserted within the reaction chamber, (c) an injector for spraying a reaction gas to the substrates, said injector being provided parallel to the substrate-supporting boat within the reaction chamber, and (d) an injector holder for supporting the injector, wherein the injector and the injector holder are detachably joined by a male-female fitting structure.
The fitting structure is preferably made of quartz so that metal contamination can be prevented. However, even if either or both of the male portion and the female portion are made of a metal, the injector can advantageously be detached and replaced. Preferably, the injector has a male end, and the injector holder has a female end. However, the other way around is also feasible. Various male-female fitting structures may be available. Preferably, a ball joint is used.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.